/Engine/Source/Editor/UnrealEd/Classes/Commandlets/DiffAssetsCommandlet.h
The meat of the commandlet, this can be called from the editor Format of commandline is as follow File1.uasset File2.uasset -DiffCmd="C:/Program Files/Araxis/Araxis Merge/AraxisP4Diff.exe {1} {2}"
true if success
static bool ExportFilesToTextAndDiff ( const [FString](API\Runtime\Core\Containers\FString) & Params )